VST 3.5 came out in 2011, VST 3.0 in 2008, VST 2.4 was released in 2006 and however sucky it is for a developer, I actually agree with Steinberg. It’s time to move on. It’s been time to move on for quite some time.
Don’t get me wrong, as a fellow developer I understand the dilemma, but I am also a consumer, and I rather get what I want for my money than just another upgrade. VST 3.5 has got something I like a lot, Note Expression.
It’s just my opinion. Good luck with your future developments, I hope to see something awesome!!!